N55.dk

Tuesday, March 27, 2012

Today we finally got the last parts transported to the workshop at Bicycle Innovation Lab and started building. The sun was shining, everything worked nicely, and to the sound of Malk de Koijn, C.V. Jørgensen and Dj Cremoso, the two first small parts of the frame took form. This was a very nice day.

Søren cuts the first piece of aluminium. It was nice to move on form the digital models to handling the materials in real life.

The two sides of the frame which will sit at the front and connect to the wheel.

Tuesday, February 21, 2012

This tuesday we have been working on some other approaches to our cargo bike. In the foggy haze of millimeter measurements, multiple sketches and various ways of construction solutions we decided that it couldn't harm to try of alternative solutions.

So why not take advantage of the old and proven design of a regular bike frame and then mix it with our design of the cargo space. This would make it a lot easier to build in the rear wheel, seat post and handlebar. Making a strong connection between the two very different parts seemed like a fun challenge. And it is still without any welding!

Tuesday, January 24, 2012

I've spent most of today adjusting the 3D model. It's still very much a work in progress, but it is getting sharper.

One of the main challenges is the mid section, where the cargo box narrows in to meet the rear frame. This is where the frame will be subject to the most stress, and since I'm not an engineer it'll be interesting to see if my guesses turn out to be right. In general I'll rather make it a bit too weak and have to strengthen it, than over-engineering it and never know.
I'm not sure about this new solution, but I'll sleep on it.

Another focus point has been the upper rear frame with the saddle, steering and handlebar. I've refined it a bit, but with this construction method it'll be hard to make it very elegant.

Here's how it looks currently. Note that the front hub is an old version. As to the rear hub and the crank box, we haven't bothered to model them as we will simply use the proven designs from the N55 space frame bikes.

Before we started the project, we did some pretty thorough googling, but were unable to find any center-hub-steering cargo bikes. Now, within the last month we have found no less than three of them. It is a bit of a bummer not being first, but we'll just have to be cheaper, lighter, faster, stronger, all round nicer and easier to build than the competition.

Here are the bikes we found:

Elian Cycles has created a beautiful bike, featuring a hub design related to what we are designing:

01 Cargo by Elian Cycles

The design and manufacture however is very much a contrast to ours. This is professional craftsmanship, requiring high levels of expertise, while our project follows a 'for dummies, by dummies' approach. Hopefully the prize tag of our bike will also be quite different. The 01 Cargo is listed as costing 3.245 euro. ($ 4.220 / 24.130 dkk)

Last is a bike with the oddly familiar name OpenCargoBike. Like the Sports Utility Bike it has a mono fork-like design. It also has a modular construction, which is related to our way of building, except this seems to require quite a lot of welding.

Tuesday, December 13, 2011

Today we are tired and content after our first trip to get materials and tools.

In the morning we took measurements on the 3D-model. It added up like this:
ca. 24 meters of aluminum

ca. 100 bolts

ca. 100 nuts

After that Andreas went and borrowed a Nihola cargo bike from the local Irma supermarket. They lend out the bikes for free. You do however have to leave 500 dkk ($90) in security, which will be repaid when the bike is returned unharmed. It's a great deal offered by the local Agenda 21 office in collaboration with Irma.

Then we were off to Glostrup, about 10 km west of Copenhagen. It was nice to get some fresh air, although it was a cold and rainy day. See map of route here.

After that we visited the friendly guys at Metalcentret. There we bought 24 meters of 25x25x2 mm aluminum square extrusions, weighing around 12 kgs and costing a 1.162 dkk ($207).

We secured it to the bike with strips and headed home. If anyone wants to do the same, some rope would probably be a better idea. Also remember to tie the extrusions to the bike in a way that they do not scratch the frame. Also remember that Metalcentret accepts cash only.

Sunday, December 11, 2011

Last week the HubJohn took its first shaky steps into physical reality. It included a couple of stumbles.

Setbacks included Søren running into a tight dealine at work, forcing us to postpone our shopping trip to Metalcenteret. Secondly the nice man at SKF revealed that the bearings we'd hoped to use for the front hub steering mechanism cost 1300 dkk / $230 a piece, which is about what we hope to pay for the entire frame. In order to make any sense the hub must be both cheap and easy to build, so it was back to the drawing board. We are now considering both off-the-shelf car-components and a CNC cut bolt-together sandwich assembly with roller bearings. Concept sketches for the sandwich are shown below. Let's see what happens when these new ideas hit reality.

Since we were not able to get the aluminum for the full scale bike this week, I picked up some balsa wood at the local hobby shop, which Søren turned into a 1:100 scale model of the lower frame. Balsa is a very soft and bendy wood, but the model proved to be nice and rigid. This seems like a good sign of the strenght of the Czech Hegehog assembly method that we are using.